Online monitoring of Aeromonas in a drinking water distribution system without chlorine

Current microbiological analyses to monitor drinking water quality take a relatively long time and continuous monitoring is not possible. However, over the last few years automatic and online microbial sensors have become available, including the Biotrack, which can specifically measure Aeromonas bacteria.

Aeromonas is the legal parameter for regrowth in the drinking water distribution network, and the current legal standard is exceeded in various distribution areas.


The Biotrack, an online sensor, can quickly and specifically detect Aeromonas bacteria. The technique is based on DNA colouration, with which the bacterial count can be determined. Further development of the underlying software could, in principle, provide information about the form in which these bacteria occur in the water. In this project we will further develop and test the Aeromonas determination with the Biotrack. We will also study its practicability for drinking water utilities, and examine the kind of data produced by the Biotrack, and how this information can be used to better understand and control the regrowth process in the distribution network.

The quick online sensor Biotrack which can detect specific bacteria within hours.


To begin with, the Biotrack’s Aeromonas determination will be validated and compared with the conventional culture method and a supplementary molecular biology technique. Afterwards, the applicability of the sensor will be researched in various practical situations to study its use for drinking water. We will also examine the sensor’s suitability in monitoring the dynamics of Aeromonas bacteria in drinking water pipes over 24 hours (day-night rhythm), and in determining whether the bacteria are present as loose cells or attached to particles, as well as the ratio of the number of living and dead bacteria present in the water. At the same time, we will examine what other data the Biotrack measurement results produce, and how these can be used, reported and interpreted.


The project’s results will provide many insights for drinking water utilities regarding the prevention of Aeromonas in drinking water, and thus strengthen understanding of the dynamics in the distribution network. By researching and building experience with these possibilities, more insight will be gained into how the sensor can be best used by potential clients and how it might be put on the market in the Netherlands and internationally.

Colonies of Aeromonas bacteria grown on a specific medium.